View all news

Top expert calls for more research to address growing health risks of climate change

Press release issued: 21 January 2025

A globally-renowned climate scientist has highlighted the need to better recognise and understand the many different adverse health effects posed by worsening climate change for current and future generations.

Dann Mitchell, Professor of Climate Science at the University of Bristol, has made the appeal in a world view op-ed published today in the journal Nature.

Prof Mitchell, who specialises in heat extremes, urged for future climate assessments to factor in the sustained impact on humans, warning that “the consequences for our bodies of repeated exposures to heat, drought, and wildfire smoke will mount.”

He is leading the UK Climate Change Risk Assessment (CCRA4) – Health and Wellbeing report for the government’s Climate Change Committee, an independent investigation of the associated risks and opportunities.

Last year marked the hottest year on record, breaching 1.5 degrees of warming for the first time since preindustrial times, and 2025 has already seen amongst the deadliest and most destructive wildfires in California history.

Some of the negative effects are clear, such as fatalities from heatstroke and increased hospital admissions of older people and babies amidst heatwaves, which put greater strain on weaker, more vulnerable bodies.

“But there’s a cumulative, longer-term toll, which needs to be studied more,” said Prof Mitchell, from the University’s Cabot Institute for the Environment and Joint Chair in Climate Hazards for the Met Office Academic Partnership (MOAP).

For instance, frequent, ongoing exposure to heatwaves and droughts may lead to higher rates of kidney disease due to regular spells of dehydration and electrolyte imbalances. Having trouble sleeping on hot, sweaty nights is often only regarded as an inconvenience but Prof Mitchell pointed out that poor quality sleep is linked to being less physically active, lower mental wellbeing, cognitive decline, and a compromised immune system.

Other consequences may be even more far-reaching and dangerous.

“The development of fetuses is affected by the conditions they and their mothers are exposed to, and will have an impact on their future health,” Prof Mitchell added.

“At the fundamental level, gene expressions can be altered by environmental stressors. For example, studies show how adults who were exposed to bouts of hot, dry weather while in the womb have an increased likelihood of high blood pressure as adults, decades on.”

Accurately and fully quantifying known public health threats presents challenges due to incomplete health data and complexities around the extent people experience different stressors.

Prof Mitchell said: “The burden of death and illness is likely to be much greater than current models can quantify.”

He called on researchers and public health officials to consider and interrogate four key areas: the varying timescales of how different health issues will manifest in a changed climate; impacts of environmental issues arising from warmer conditions; socio-economic consequences of climate-related disasters; and incorporating the findings from wide-ranging research on these issues into global climate risk assessments.

Examples of such lesser-known public health issues include increased salinity of groundwater due to sea level rise resulting in more cases of hypertension among coastal communities, and more cases of respiratory conditions as a result of poor air quality in the wake of wildfires. Extreme weather events, such as hurricanes, can have serious lasting consequences, such as weakened social networks as people relocate and public spending budgets are redirected to recovery efforts.

Prof Mitchell concluded: “Even if the outcomes are uncertain, researchers must quantify this health burden…Once we do this, we will see that the health burden of climate change is far more substantial than we have realised.”

Combining results from disparate data and analytical insights from interdisciplinary experts will help facilitate more informed discussions about how to tackle this pressing public health threat. 

The University of Bristol is at the forefront of addressing some of the world’s biggest challenges; reaching net zero and tackling climate change is a key research priority.

‘Climate change’s effects on human health are mounting,’ a world view by Dann Mitchell in Nature

Edit this page